This invention relates to ink formulations containing curable polymeric fixing agents.
Printing inks containing a dye or pigment and a cationic fixing agent such as a polyamide amine or a polyethylene imine are known. However, the printings obtained with such inks on nonwoven fabrics and particularly on tissue paper do not exhibit satisfactory fastnesses towards a large number of agents, e.g., alcohol, milk, alkali, acid, solvents, detergents, etc., so that the printed nonwoven fabrics may not be used for e.g., various domestic tasks without bleeding. When the cationic fixing agent is a polyamide amine, the printing inks must also contain a volatile amine or ammonia to inhibit premature reaction between the cationic fixing agent and dyes. This confers an unpleasant odor to the printed nonwoven fabric, particularly when this is immediately rolled up after the printing in a continuous production process. Furthermore, these inks often contain further additives such as a binding agent, e.g., a saponifiable derivative or a saponifiable maleic resin, and their pH exceeds 9 to improve their stability in storage so that they are not compatible with most pigments and dyes.
In view of the foregoing deficiencies of conventional ink formulations, it is desirable to provide an ink formulation which is odorless and exhibits improved fastness after application.